A randomized, parallel group, double-blind study of ticagrelor compared with aspirin for prevention of vascular events in patients undergoing coronary artery bypass graft operation: Rationale and design of the Ticagrelor in CABG (TiCAB) trial: An Investigator-Initiated trial

Sex differences among patients receiving ticagrelor monotherapy or aspirin after coronary bypass surgery: A prespecified subgroup analysis of the TiCAB trial

BACKGROUND

There is limited evidence on the association of sex with outcomes among patients undergoing coronary bypass surgery (CABG) and treated with ticagrelor monotherapy or aspirin.

METHODS

This was a pre-specified sub-analysis of TiCAB, an investigator-initiated placebo-controlled randomized trial. Primary efficacy endpoint was the composite of cardiovascular death, myocardial infarction, stroke, or repeat revascularization 1 year after CABG. Safety endpoint was BARC type 2, 3 or 5 bleeding.

RESULTS

A total of 280 (15.0%) women and 1579 (85.0%) men were included. Compared with men, women were older (66.1 ± 10.2 vs. 70.1 ± 9.3 years) with more acute presentation (17.0% vs 21.1%). The incidence of the primary endpoint was similar between women and men (9.2% vs. 8.9%, HR 1.08, 95%CI 0.71-1.66, P = 0.71). Cardiovascular death occurred more often in women (2.9% vs 1.0%, adjusted HR 2.87, 95%CI 1.23-6.70, P = 0.02). The incidence of bleeding was similar between the sexes (2.2% vs. 2.5%, HR 0.91, 95% CI 0.51-1.65, P = 0.77). Ticagrelor vs aspirin was associated with a similar risk of the primary endpoint in women (10.6% vs. 7.9%, HR 1.39, 95%CI 0.63-3.05, P = 0.42) and men (9.5% vs. 8.2%, HR 1.15, 95%CI 0.82-1.62, P = 0.41;p_interaction = 0.69), and a similar risk of bleeding in women (2.9% vs. 1.4%, HR 2.09, 95%CI 0.38-11.41, P = 0.40) and men (2.2% vs. 2.8%, HR 0.80, 95%CI 0.42-1.52, P = 0.49;p_interaction = 0.35).

CONCLUSIONS

Among women and men undergoing CABG, ticagrelor monotherapy was associated with a similar risk of the primary efficacy endpoint and bleeding compared with aspirin. The risk of cardiovascular death was increased in women irrespective of antiplatelet therapy.

CYP2C19 genotype and platelet aggregation test-guided dual antiplatelet therapy after off-pump coronary artery bypass grafting: A retrospective cohort study

Background

Dual antiplatelet therapy (DAPT) is recommended in patients undergoing off-pump coronary artery bypass graft surgery (OPCAB). Clopidogrel is less effective among patients with loss-of-function (LoF) of CYP2C19 alleles, while ticagrelor has direct effects on P2Y₁₂ receptor. Whether a CYP2C19 genotype plus platelet aggregation test (PAgT)-guided DAPT after CABG could improve clinical outcomes remain uncertain.

Materials and methods

From August 2019 to December 2020, 1,134 consecutive patients who underwent OPCAB received DAPT for 1 year after surgery in Ruijin Hospital, Shanghai Jiao Tong University School of Medicine. According to the actual treatment they received in real-world, 382 (33.7%) of them received a traditional DAPT: aspirin 100 mg qd + clopidogrel 75 mg qd, no matter the CYP2C19 genotype and response in platelet aggregation test (PAgT). The other 752 (66.3%) patients received an individual DAPT based on CYP2C19 genotype and PAgT: aspirin 100 mg qd + clopidogrel 75 mg qd if CYP2C19 was extensive metabolizer, or moderate metabolizer but normal response in PAgT; aspirin 100 mg qd + ticagrelor 90 mg bid if CYP2C19 was poor metabolizer, or moderate metabolizer but no or low response in PAgT. One-year follow-up was achieved for all patients. The primary outcome was major adverse cardiovascular events (MACE), a composite of cardiovascular death, myocardial infarction, and stroke. The safety outcome was thrombolysis in myocardial infarction (TIMI) criteria major bleeding.

Results

Compared with the traditional DAPT group, the risk of MACE in the individual DAPT group was significantly lower (5.5 vs. 9.2%, HR 0.583; 95% CI, 0.371-0.915; P = 0.019), mainly due to the decreased risk of MI (1.7 vs. 4.2%, HR 0.407; 95% CI, 0.196-0.846; P = 0.016). The risk of TIMI major bleeding events was similar between the two groups (5.3 vs. 6.0%, RR 0.883; 95% CI, 0.537-1.453; P = 0.626).

Conclusion

For patients who underwent OPCAB, individual DAPT (CYP2C19 genotype plus PAgT-guided strategy) was associated with a lower risk of MACE and a similar risk of major bleeding.

A Randomized Trial of Clopidogrel vs Ticagrelor After Off-Pump Coronary Bypass

BACKGROUND

This study aimed to compare the outcomes of aspirin in combination with either ticagrelor or clopidogrel after off-pump coronary artery bypass (OPCAB) in patients with clopidogrel resistance.

METHODS

Between November 2014 and November 2020, 1739 patients underwent OPCAB. Aspirin and clopidogrel treatment was initiated the day after surgery. On postoperative days 7 to 9, clopidogrel resistance was evaluated using a point-of-care assay. A total of 278 (18.9%) patients had clopidogrel resistance ( platelet reaction unit >208) and were enrolled in the study. The study investigators excluded patients with coresistance to aspirin (n = 74) and divided the remaining patients (mean age, 67.4 ± 8.5 years) into 2 groups (an aspirin and ticagrelor group [AT group; n = 102] and an aspirin and clopidogrel group [AC group; n = 102]), randomly assigned using a 1:1 ratio block table. The primary end point was graft patency and major adverse cardiovascular events (MACEs; defined as the composite of cardiovascular mortality, myocardial infarction, and repeat revascularization at 1 year after OPCAB), and the coprimary end point was the graft patency rate. The data were analyzed using the intent-to-treat method.

RESULTS

The graft occlusion rates in the AT and AC groups were 3.9% and 5.9%, respectively (P = .52). Neither death from cardiovascular causes (1.0% vs 2.9%; P = .32) nor myocardial infarction showed significant differences (1.0% vs 3.9%; P = .18). No significant difference in the rates of major bleeding were found between the 2 groups (P = .75). However, the AT group was associated with a lower rate of MACEs after OPCAB (hazard ratio, 0.77; 95% CI, 0.684-0.891; P = .01).

CONCLUSIONS

These results suggest that ticagrelor may be associated with reducing MACEs in patients with clopidogrel resistance after OPCAB.

Ticagrelor monotherapy versus aspirin in patients undergoing multiple arterial or single arterial coronary artery bypass grafting: insights from the TiCAB trial

OBJECTIVES

We evaluated the effect of ticagrelor monotherapy on outcomes after multiple arterial grafting (MAG) or single arterial grafting (SAG) in coronary artery bypass grafting (CABG).

METHODS

In a post hoc, non-randomized analysis of the TiCAB (Ticagrelor in CABG; ClinicalTrials.gov NCT01755520) trial, we compared event rates for ticagrelor versus aspirin in patients undergoing MAG and SAG. Primary outcome was the composite of cardiovascular death, non-fatal myocardial infarction (MI), stroke or repeat revascularization 1 year after CABG. Secondary outcomes included individual components of the primary end point, all-cause death and bleeding.

RESULTS

Among 1753 patients, 998 patients underwent MAG and 755 patients underwent SAG. There was no significant difference in the 1-year primary composite outcome for ticagrelor versus aspirin with MAG [7.2% vs 7.9%; hazard ratio (HR) 0.90, 95% confidence interval (CI) 0.57-1.43; P = 0.66] or SAG (12.3% vs 8.6%; HR 1.47, 95% CI 0.93-2.31; P = 0.10). Event rates for cardiovascular death, MI, stroke, repeat revascularization and all-cause death were similar for both treatment groups with MAG and SAG. No significant difference in major bleeding was observed for ticagrelor versus aspirin with MAG (2.6% vs 2.7%; HR 0.95, 95% CI 0.44-2.05; P = 0.90) or SAG (5.8% vs 4.0%; HR 1.49, 95% CI 0.77-2.89; P = 0.24).

CONCLUSIONS

In patients undergoing either MAG or SAG in the TiCAB trial, ticagrelor monotherapy compared with aspirin did not affect the rate of cardiovascular death, non-fatal MI, stroke or repeat revascularization, or the rate of bleeding, at 1 year after CABG.

Ticagrelor or aspirin after coronary artery bypass in patients with chronic kidney disease

BACKGROUND

The optimal antiplatelet therapy for patients with chronic kidney disease (CKD) undergoing coronary artery bypass grafting (CABG) remains unknown.

METHODS

This post hoc analysis of the Ticagrelor in Coronary Artery Bypass (TiCAB) trial examined the efficacy and safety of ticagrelor versus aspirin in patients with or without CKD. Primary endpoint was the composite of cardiovascular death, stroke, myocardial infarction or revascularization (MACCE) at 1 year after CABG. Secondary endpoints included individual components of the primary endpoint, all-cause death, and major bleeding.

RESULTS

CKD was present in 276 of 1,843 randomized patients (15.0%). Patients with CKD versus those without CKD had higher 1-year rates of MACCE (13.0% vs. 8.3%, HR 1.63, 95% CI 1.12-2.39, P=0.01) and major bleeding (5.6% vs. 3.1%, HR 1.84, 95% CI 1.03-3.28, P=0.04). The 1-year rate of MACCE was increased with ticagrelor versus aspirin in patients with CKD (18.2% vs. 8.9%, HR 2.15, 95% CI 1.08-4.30, P=0.03), but not in patients without CKD (8.5% vs. 8.1%, HR 1.05, 95% CI 0.74-1.49, P=0.79) (P_interaction=0.067). There was no difference in the 1-year rate of major bleeding with ticagrelor versus aspirin in patients with CKD (6.6% vs. 4.7%, HR 1.44, 95% CI 0.52-3.97, P=0.48) and without CKD (3.3% vs. 2.9%, HR 1.14, 95% CI 0.64-2.01, P=0.65).

CONCLUSIONS

In patients with CKD and CABG, those who received ticagrelor had a higher incidence of MACCE but a similar incidence of major bleeding compared to those who received aspirin.

Aspirin plus ticagrelor or clopidogrel on graft patency one year after coronary bypass grafting: a single-center, randomized, controlled trial

Background

Dual antiplatelet therapy (DAPT) improves early post-operative graft patency, but the optimal DAPT strategy for the patients after coronary artery bypass grafting (CABG) has not been confirmed. We sought to evaluate the effect of aspirin plus ticagrelor versus aspirin plus clopidogrel on saphenous vein graft (SVG) patency within 1 year after CABG.

Methods

Between October 2017 and December 2018, 147 consecutive patients undergoing elective CABG at Changhai Hospital were randomized into two groups: group AT, receiving aspirin 100 mg/d plus ticagrelor 2×90 mg/d; group AC, receiving aspirin 100 mg/d plus clopidogrel 75 mg/d. Both DAPTs should be administered within 24 h when clinical stability was ensured. 64-multislice computed tomography angiography (MSCTA) was used to assess the graft patency at 12 months after CABG.CYP2C19 gene variants were measured to assess the clopidogrel efficacy on graft patency.

Results

Among the 147 participants who completed the study, one (0.7%) patient from the AC group died at 5 weeks after surgery due to severe infection. All other patients were treated with DAPT for 12 months and underwent 64-MSCTA according to schedule. There were no significant differences in pre-operative characteristics and intraoperative transit-time flow measurement findings between the two groups. Besides, no significant differences in the incidence of major adverse cardiac events (MACEs) and major bleeding were observed. A 64-MSCTA showed that SVG patency was 91.0% (141 of 155) in the AT group and 89.9% (161 of 179) in the AC group (P=0.751). No significant associations were found between different CYP2C19 genotypes and SVG patency (P>0.05).

Conclusions

Either aspirin plus ticagrelor or aspirin plus clopidogrel can maintain a fairly high graft patency rate in the early phase after CABG, regardless of CYP2C19 genotypes.

Clinical outcomes of complete versus incomplete revascularization in patients treated with coronary artery bypass grafting: insights from the TiCAB trial

OBJECTIVES

In this post hoc analysis of the Ticagrelor in coronary artery bypass grafting (CABG) trial, we aimed to analyse patients treated with CABG receiving either complete revascularization (CR) or incomplete revascularization (ICR) independent from random allocation to either ticagrelor or aspirin.

METHODS

Of 1859 patients enrolled in the Ticagrelor in CABG trial, 1550 patients (83.4%) received CR and 309 patients (16.6%) ICR. Outcomes were evaluated regarding all-cause mortality, cardiovascular death, myocardial infarction (MI), repeat revascularization, stroke and bleeding within 12 months after CABG.

RESULTS

Baseline parameters revealed significant differences regarding clinical presentation (stable angina pectoris: CR 68.9% vs ICR 71.2%, instable angina pectoris: 14.1% vs 7.8%, non-ST elevation MI: 17.0% vs 21.0%, P ˂ 0.01), lesion characteristics (chronic total occlusion: CR 91.3% vs ICR 96.8%, P ˂ 0.01), operative technique [off-pump coronary artery bypass surgery (OPCAB): CR 3.0% vs ICR 6.1%, P ˂ 0.01] and number of utilized grafts (total number of grafts: 2.69/patient vs 2.49/patient, P ˂ 0.001). ICR patients displayed a significantly increased risk of repeat revascularization [hazard ratio (HR) 1.91, 95% confidence interval (CI) 1.16-3.16; P < 0.01] and percutaneous coronary intervention (HR 1.95, 95% CI 1.13-3.35; P < 0.05) within 12 months after CABG. Higher risk for repeat revascularization in ICR patients was independent from random allocation to either ticagrelor or aspirin and persisted after adjustment for baseline imbalances.

CONCLUSIONS

Patients with ICR presented more stable at the time of admission, but received less grafts, highly likely due to a higher rate of chronic total occlusion lesions and performed OPCAB. Although mortality presented no difference between groups, our results suggest that patients benefit from CR with regard to prevention of repeat revascularization.

Randomized trial of ticagrelor vs. aspirin in patients after coronary artery bypass grafting: the TiCAB trial

Aims

The antiplatelet treatment strategy providing optimal balance between thrombotic and bleeding risks in patients undergoing coronary artery bypass grafting (CABG) is unclear. We prospectively compared the efficacy of ticagrelor and aspirin after CABG.

Methods and results

We randomly assigned in double-blind fashion patients scheduled for CABG to either ticagrelor 90 mg twice daily or 100 mg aspirin (1:1) once daily. The primary outcome was the composite of cardiovascular death, myocardial infarction (MI), repeat revascularization, and stroke 12 months after CABG. The main safety endpoint was based on the Bleeding Academic Research Consortium classification, defined as BARC ≥4 for periprocedural and hospital stay-related bleedings and BARC ≥3 for post-discharge bleedings. The study was prematurely halted after recruitment of 1859 out of 3850 planned patients. Twelve months after CABG, the primary endpoint occurred in 86 out of 931 patients (9.7%) in the ticagrelor group and in 73 out of 928 patients (8.2%) in the aspirin group [hazard ratio 1.19; 95% confidence interval (CI) 0.87–1.62; P = 0.28]. All-cause mortality (ticagrelor 2.5% vs. aspirin 2.6%, hazard ratio 0.96, CI 0.53–1.72; P = 0.89), cardiovascular death (ticagrelor 1.2% vs. aspirin 1.4%, hazard ratio 0.85, CI 0.38–1.89; P = 0.68), MI (ticagrelor 2.1% vs. aspirin 3.4%, hazard ratio 0.63, CI 0.36–1.12, P = 0.12), and stroke (ticagrelor 3.1% vs. 2.6%, hazard ratio 1.21, CI 0.70–2.08; P = 0.49), showed no significant difference between the ticagrelor and aspirin group. The main safety endpoint was also not significantly different (ticagrelor 3.7% vs. aspirin 3.2%, hazard ratio 1.17, CI 0.71–1.92; P = 0.53).

Conclusion

In this prematurely terminated and thus underpowered randomized trial of ticagrelor vs. aspirin in patients after CABG no significant differences in major cardiovascular events or major bleeding could be demonstrated.

ClinicalTrials.gov Identifier

NCT01755520.

Pharmacokinetic and Pharmacogenetic Factors Contributing to Platelet Function Recovery After Single Dose of Ticagrelor in Healthy Subjects

Objectives: This study aimed to elucidate the contribution of candidate single nucleotide polymorphisms (SNPs) related to pharmacokinetics on the recovery of platelet function after single dose of ticagrelor was orally administered to healthy Chinese subjects.

Methods: The pharmacokinetic profiles of ticagrelor and its metabolite AR-C124910XX (M8), and the platelet aggregation (PA), were assessed after 180 mg of single-dose ticagrelor was orally administered to 51 healthy Chinese subjects. Effects of CYP2C19^*2, CYP2C19^*3, CYP3A5^*3, UGT1A1^*6, UGT1A1^*28, UGT2B7^*2, UGT2B7^*3, SLCO1B1 388A>G, and SLCO1B1 521T>C, on the pharmacokinetics of ticagrelor and M8, and platelet function recovery were investigated.

Results: The time to recover 50% of the maximum drug effect (RT₅₀) ranging from 36 to 126 h with 46.9% CV had a remarkable individual difference and was positively associated with the half-life (t_1/2) of M8 (r = 0.3901, P = 0.0067). The time of peak concentration (T_max) of ticagrelor for CYP2C19^*3 GG homozygotes was significantly higher than that of GA heterozygotes (P = 0.0027, FDR = 0.0243). Decreased peak concentration (C_max) of M8 was significantly associated with SLCO1B1 388A>G A allele (P = 0.0152, FDR = 0.1368). CYP2C19^*2 A was significantly related to decreased C_max of M8 (P = 0.0455, FDR = 0.2048). While, the influence of these nine SNPs on the recovery of platelet function was not significant.

Conclusion: Our study suggests that the elimination of M8 is an important factor in determining the recovery of platelet function. Although CYP2C19 and SLCO1B1 genetic variants were related to the pharmacokinetics of ticagrelor or M8, they did not show a significant effect on the platelet function recovery in this study.

Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT03092076, identifier: NCT03092076

Impact of ticagrelor versus aspirin on graft patency after CABG: Rationale and design of the TARGET (ticagrelor antiplatelet therapy to reduce graft events and thrombosis) randomized controlled trial (NCT02053909)

RATIONALE

Saphenous vein graft disease remains a major limitation of coronary artery bypass graft surgery (CABG). Up to 20% of vein grafts will occlude within the first year after CABG despite standard aspirin antiplatelet therapy. However, more potent postoperative platelet inhibition with ticagrelor may improve graft patency. The goal of this study will be to evaluate the efficacy of ticagrelor, as compared to aspirin, for the prevention of saphenous vein graft occlusion following CABG.

STUDY DESIGN

The Ticagrelor Antiplatelet Therapy to Reduce Graft Events and Thrombosis (TARGET) study is a multi-center double-blind randomized controlled trial enrolling patients who have undergone multi-vessel CABG with at least one saphenous vein graft. Patients are being randomized to receive either aspirin 81 mg twice per day or ticagrelor 90 mg twice per day for 2 years starting within 7 days after surgery. The projected enrollment is 150 patients in each arm (300 total patients). Patients will undergo computed tomography (CT) coronary angiography at 1 and 2 years after surgery to assess the incidence of vein graft occlusion and stenosis.

CONCLUSION

To our knowledge, this trial is the first prospective study to evaluate the impact of early postoperative ticagrelor on 1- and 2-year graft patency after CABG. Furthermore, it is also the first trial to use a novel antiplatelet agent as a standalone, without aspirin, after CABG. Should ticagrelor reduce the incidence of postoperative graft occlusion, the results of this study will redefine modern antiplatelet management following coronary bypass surgery (ClinicalTrials.govNCT02053909).

Ticagrelor - toward more efficient platelet inhibition and beyond

Novel antiplatelet drugs, including ticagrelor, are being successively introduced into the therapy of atherothrombotic conditions due to their superiority over a standard combination of clopidogrel with acetylsalicylic acid in patients with acute coronary syndromes (ACS). A P2Y12 receptor antagonist, ticagrelor, is unique among antiplatelet drugs, because ticagrelor inhibits the platelet P2Y12 receptor in a reversible manner, and because it demonstrates a wide palette of advantageous pleiotropic effects associated with the increased concentration of adenosine. The pleiotropic effects of ticagrelor comprise cardioprotection, restoration of the myocardium after an ischemic event, promotion of the release of anticoagulative factors and, eventually, anti-inflammatory effects. Beyond the advantageous effects, the increased concentration of adenosine is responsible for some of ticagrelor's adverse effects, including dyspnea and bradycardia. Large-scale clinical trials demonstrated that both standard 12-month therapy and long-term use of ticagrelor reduce the risk of cardiovascular events in patients with ACS, but at the expense of a higher risk of major bleeding. Further trials focused on the use of ticagrelor in conditions other than ACS, including ischemic stroke, peripheral artery disease and status after coronary artery bypass grafting. The results of these trials suggest comparable efficacy and safety of ticagrelor and clopidogrel in extra-coronary indications, but firm conclusions are anticipated from currently ongoing studies. Here, we summarize current evidence on the superiority of ticagrelor over other P2Y12 antagonists in ACS, discuss the mechanism underlying the drug-drug interactions and pleiotropic effects of ticagrelor, and present future perspectives of non-coronary indications for ticagrelor.

Dual Antiplatelet Therapy Versus Aspirin Monotherapy in Diabetics With Multivessel Disease Undergoing CABG: FREEDOM Insights

BACKGROUND

Clinical practice guidelines recommend post-operative dual antiplatelet therapy (DAPT) in patients who undergo coronary artery bypass grafting (CABG) following acute coronary syndromes (ACS).

OBJECTIVES

The authors have evaluated DAPT utilization rates and associated outcomes among post-CABG patients with diabetes.

METHODS

In a post hoc, nonrandomized analysis from the FREEDOM (Future REvascularization Evaluation in patients with Diabetes mellitus: Optimal management of Multivessel disease) trial, we compared patients receiving DAPT (aspirin plus thienopyridine) and aspirin monotherapy at 30 days post-operatively. The primary outcome was the risk adjusted 5-year FREEDOM composite of all-cause mortality, nonfatal myocardial infarction, or stroke. Safety outcomes included major bleeding, blood transfusion, and hospitalization for bleeding.

RESULTS

At 30 days post-CABG, 544 (68.4%) patients received DAPT and 251 (31.6%) patients received aspirin alone. The median (25th, 75th percentile) duration of clopidogrel therapy was 0.98 (0.23 to 1.91) years. There was no significant difference in the 5-year primary composite outcome between DAPT- and aspirin-treated patients (12.6% vs. 16.0%; adjusted hazard ratio [HR]: 0.83; 95% confidence interval [CI]: 0.54 to 1.27; p = 0.39). The 5-year primary composite outcomes were similar for patients receiving DAPT versus aspirin monotherapy respectively, in subgroups with pre-CABG ACSs (15.2% vs. 16.5%; HR: 1.06; 95% CI: 0.53 to 2.10; p = 0.88) and those with stable angina (11.6% vs. 15.8%; HR: 0.82; 95% CI: 0.50 to 1.343; p = 0.42). The composite outcomes of both treatment groups were also similar by SYNTAX score, duration of DAPT therapy, completeness of revascularization, and in off-pump CABG. No treatment-related differences in major bleeding (5.6% vs. 5.7%; HR: 1.00; 95% CI: 0.50 to 1.99; p = 0.99), blood transfusions (4.8% vs. 4.5%; HR: 1.09; 95% CI: 0.51 to 2.34; p = 0.82), or hospitalization for bleeding (2.6% vs. 3.3%; HR: 0.85; 95% CI: 0.34 to 2.17; p = 0.74) were observed between aspirin- and DAPT-treated patients, respectively.

CONCLUSIONS

The use of DAPT in patients with diabetes post-CABG in our cohort was high. Compared with aspirin monotherapy, no associated differences were observed in cardiovascular or bleeding outcomes, suggesting that routine use of DAPT may not be clinically warranted. (Future REvascularization Evaluation in patients with Diabetes mellitus: Optimal management of Multivessel disease [FREEDOM]; NCT00086450).